Submitted on: 11 November 2011.
Revised on: 05 February 2012.
Accepted on: 24 February 2012.
___________________International Journal of Management Science and Engineering Management
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Submitted on: 14 June 2003.
Revised on: 06 August 2003.
Accepted on: 05 September 2003.
___________________International Journal of Management Science and Engineering Management